Andricus koreanus Kang & Jung, 2025

Kang, Minjoon & Jung, Sunghoon, 2025, A new species of Andricus Hartig (Hymenoptera: Cynipidae: Cynipini) from South Korea, Andricus koreanus sp. nov., Zootaxa 5660 (1), pp. 119-124 : 120-123

Andricus koreanus Kang & Jung , sp. nov.

( Figure 1 )

Type material. HOLOTYPE ♀ with the following collection data: ‘242-1 Jungang-ro, Suncheon-si, Jeollanam-do, South Korea’ (white label) / ‘Ex. cryptic leaf galls on Q. mongolica ( Quercus section), 27.V.2021 (collected), 27.V.2021 (emerged), S.B Choi leg.’ (white label) / ‘Holotype ♀ Andricus koreanus Kang & Jung , desig. Kang 2021’ (red label), ( CNU). PARATYPES (33♂ & 27♀) with data as the holotype. All type specimens are deposited in CNU .

Etymology. The new species is named after the country of the type locality, South Korea. Noun in apposition.

Diagnosis. Andricus koreanus sp. nov. is morphologically similar to A. pseudocurvator ( Tang & Melika, 2011) but differs from this species by having the body length about 1.5–1.6 mm (1.9–2.1 mm in A. pseudocurvator ); POL 2.1x as long as OOL (1.4x in A. pseudocurvator ), OOL 1.4x as long as length of lateral ocellus (2.5x in A. pseudocurvator ); ventral spine of hypopygium (the prominent part) 2.0x as long as broad in ventral view (6.0x longer than broad in A. pseudocurvator ) radial cell about 3.5x as long as broad (about 3.3x in A. pseudocurvator ); all subsequent tergites without setae (with some white setae laterally, all subsequent tergites with setae, smooth and shiny in A. pseudocurvator ). In male, A. koreanus body length about 1.3–1.4 mm (1.8–1.9 mm in A. pseudocurvator ); A. koreanus F1 straight (F1 curved and swollen apically in A. pseudocurvator ); F1 1.2x longer than F2 and nearly 2.0x longer than pedicel, F13 1.3x longer than F12 (F1 1.2x longer than F2 and nearly 2.5x longer than pedicel; F13 equal in length to F 12 in A. pseudocurvator ). Furthermore, the new species was reared from cryptic flat leaf galls, whereas A. pseudocurvator develop in the leaf lamina integrated in the leaves.

Description. FEMALE ( Fig. 1A ). Length. Body length about 1.5–1.6 mm (n = 15)

Color ( Fig. 1A ). Body mainly dark brown; head and mesosoma brown; maxillary and labial palps, and legs, yellowish brown; clypeus brown; mandibles light brown with dark brown tips; basal part of coxa dark brown; wings hyaline, veins pale brown, nucha dark brown; metasoma uniformly dark chestnut, with lighter hypopygium.

Head. Mainly coriaceous, with frons, vertex and genae covered with sparse short white setae ( Fig. 1B ). Head rounded in frontal view, almost 1.2x as broad as high, genae very slightly broadened behind compound eye; malar space almost 0.4x as long as height of compound eye; malar space smooth, malar sulcus absent; lower face with striae radiating from both sides of clypeus and almost reaching eyes and toruli; striae not extending into the space between eyes and toruli; clypeus small, impressed. ventrally straight, emarginate, with small elevated central area; anterior tentorial pits distinct; epistomal and clypeo-pleurostomal sulci distinct, transfacial distance 1.3x as long as height of eye; toruli situated slightly under mid-height of compound eyes; distance between eye and torulus slightly longer than diameter of torulus; diameter of torulus slightly longer than distance between toruli; frons coriaceous, lateral frontal carina absent ( Fig. 1B ); Head in dorsal view slightly broader than mesosoma, nearly 2.3x as broad as long; vertex coriaceous; Compound eyes converging ventrally; POL 2.1x as long as OOL and 1.6x as long as LOL; OOL 1.4x as long as length of lateral ocellus ( Fig. 1C ). Vertex and occiput delicately coriaceous to alutaceous ( Fig. 1C ). Postocciput and postgena smooth, shiny, without setae; posterior tentorial pit distinct, ovate, deep, area below not impressed; height of occipital foramen nearly equal to height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulcus ( Fig. 1E ).

Antenna ( Fig. 1D ). 11-flagellomeres (in some paratype females indistinct suture present and antenna seems to be with 12 flagellomeres); longer than mesosoma, filiform, with short pubescence; F1 1.1x as long as pedicel; F1 1.1x as long as F2, F2 1.3x as long as F3, last flagellomere about 1.9x as long as F10; placodeal sensilla visible on flagellar segments F7–F11. Antenna Ratio of flagellomeres. 1–12: 4.25: 4: 3: 3: 3: 3: 2.75: 2.75: 2.5: 2.5: 4.75 (suture between F12 and F11 indistinct).

Mesosoma. About 1.3x as long as high in lateral view including nucha, slightly convex, with short and not dense pubescence; pronotum coriaceous to smooth, with sparse white setae; propleuron smooth and shiny, with smooth area centrally without striae and sparse white setae ( Fig. 1H ); mesoscutum about 1.2x as wide as long; notauli complete, deep, distinctly impressed, reaching anterior margin of mesoscutum; anterior parallel and parapsidal lines shallow to indistinct, anterior parallel lines extending to 1/5 of the mesoscutal length; median mesoscutal line indistinct; parascutal carina indistinct; mesoscutellum about as long as broad, quadrangular, uniformly coriaceous, dull rugose, overhanging metanotum; scutellar foveae distinct, deep, transversely ovate, broader than high, with smooth, shiny bottom, with distinct elevated narrow smooth median carina, separating foveae; dorsoaxillar area coriaceous; subaxillular bar smooth, shiny ( Fig. 1F ). Mesopleuron smooth, shiny, with sparse white setae; metapleural sulcus almost reaching posterior margin of mesopectus in upper 1/4 of its height ( Fig. 1A ). Propodeum with white setae laterally, central propodeal area smooth, lateral propodeal carina very slightly curved outward, nucha short with weakly sulcate ( Fig. 1G ).

Fore wings ( Fig. 1I ). Length about 1.2 mm. Longer than body length, forewing about 4.0x as long as broad, dense cilia on margin, radial cell open, about 3.5x as long as broad; R1 and Rs reaching the wing margin and slightly curved; Rs+M indistinct, M distinct; Rs+M not reaching M.

Legs. With short white setae; tarsal claws with basal lobe ( Fig. 1J ).

Metasoma. Slightly longer than head+mesosoma and 1.3x as long as high in lateral view; 2nd metasomal tergite occupying 1/3–1/2 length of metasoma in dorsal view, all subsequent tergites without setae, smooth and shiny. Ventral spine of the hypopygium short, prominent part 2.0x as long as broad in ventral view, with some white setae along ventral part of hypopygium ( Fig. 1A ).

MALE ( Fig. 1K ). Body length about 1.3–1.4 mm (n = 13); POL:OOL:LOL=4:3:2; Antenna Ratio of flagellomeres. 1–13: 11, 8, 7.5, 7.5, 7, 6.5, 6.5, 6, 6, 5.5, 5.5, 5, 6.5. Fore wing length about 1.1 mm.

Asexual Generation FEMALE. Unknown.

Host Plants. Quercus mongolica .

Gall ( Fig. 1M ). Sexual generation. Occur on the underside of the leaf, rounded and flattened about 2.0 mm diameter, not forming clusters, the upperside of the leaf is swollen, green. The average number of larval chambers per gall is 2–3. The cryptic nature of these galls makes it difficult to distinguish an attacked leaf from a non-attacked one before the emergence of the adults, when the emergence holes are formed.

Distribution. South Korea (Jeollanam-do).

Phenology. Mature galls were collected in late May, adults emerging immediately after the galls were collected, in late May.

Figures

FIGURE 1. Andricus koreanus Kang & Jung, sp. nov. sexual generation paratype: A) habitus in lateral view, female; B) head in anterior view; C) head in dorsal view; D) antenna, female; E) head in posterior view; F) mesosoma in dorsal view; G) propodeum; H) pronotum and propleuron; I) fore wing; J) tarsal claw; K) habitus in lateral view, male; L) antenna, male; M) gall. Scale bars = 0.5 mm.